1. Field of the Invention
The present invention relates to signal switching devices. More specifically, the present invention relates to apparatus for switching a plurality of signals in communication networks.
While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
2. Description of the Related Art
Parallel processors commonly include a large number of processors that execute programs concurrently or in parallel. These architectures typically require a communication network that allows efficient data transfer between processors, and between an individual processor and its associated memories. In many parallel processing systems it is desirable to permit many processors to transfer information simultaneously. Employing optics in parallel processing is particularly effective given the relatively large bandwidth attainable, and the typically low interaction among individual optical beams in linear media. One optical system used in this context is known as a crossbar network. A crossbar network permits a plurality of processors or memories to be dynamically interconnected in a selected configuration without mechanically moving existing interconnections.
Certain crossbar networks are realized completely electronically. That is, resort is not made to the optical domain until a selected number of input data channels have been placed in electrical communication with a desired array of output channels. Only then is data present on the electrical output channels used to modulate an optical carrier, which is subsequently transmitted to a selected destination. Unfortunately, this mode of electronic switching is relatively slow and may impede the overall speed of the computing network in which it is utilized.
Alternatively, other crossbar networks are operative entirely in the optical domain. Specifically, a selected number of optical input beams are interconnected via optical elements to a chosen set of optical output channels.
Unfortunately, channel switching effected entirely in the optical domain is slow, as is channel switching entirely in the electronic domain. Moreover, conventional exclusively optical switching networks are marked by poor interchannel isolation. That is, adjacent optical channels are prone to substantial mutual interference which may degrade overall system performance.
Hence, a need in the art exists for a crossbar switch capable of providing a high switch rate while maintaining acceptable interchannel isolation.